Such a turbine blade is known for example from WO 2005/003517 A1. The blade walls which form the blade airfoil enclose a cavity on the inside in which cooling air can flow. Furthermore, further passages for guiding a second medium, specifically fuel, are provided in the blade wall of the turbine blade. Holes extend through the blade wall of the turbine blade, through which holes the cooling medium which flows inside the turbine blade can discharge outwards into a hot gas space. In order to produce a combustible mixture, connecting passages, which connect the fuel-guiding passages to the through-holes, are provided in the blade wall. As a result, fuel can be mixed with cooling air still inside the through-holes and as a combustible mixture can be blown out into the hot gas which flows around the turbine blade. With such a turbine blade, both the hot gas which flows through the turbine and the cooling air which discharges from the turbine blade can be reheated as a result of the combustion of the mixture, which in general is carried out for increasing the level of performance of the gas turbine, for reducing the pollutant emissions and for improving the efficiency of the gas turbine, and is known as a form of carnotization.
Furthermore, a combustion chamber with a multiplicity of porous heat-shield elements is known from WO 99/46540 A1, by means of which a combustible mixture can be subsequently introduced into the combustion chamber of a gas turbine, i.e. outside the burners of the gas turbine.
A turbine blade with a multiplicity of internally arranged cooling passages which extend from the blade root towards the blade tip and also formed in a meandering configuration in the process, is known from EP 0 896 127 A2. The cooling passages are connected to altogether three root-side openings for feeding cooling air of different quality. One of the openings is connected to a rectilinear cavity which extends from the blade root to approximately the blade tip. This cavity is directly adjacent to the trailing edge of the blade airfoil of the turbine blade and is in flow communication with the discharge openings which are arranged on the trailing edge. The cooling medium which is fed through the corresponding root-side opening can flow through the cavity and can leave the trailing edge via the discharge openings over the approximately entire length of the trailing edge with a cooling effect in the process. At the same time, the turbine blade has a further cavity, on the blade-tip-side end of which a cooling passage, which extends transversely to the longitudinal extent of the blade airfoil, is provided. This cooling passage leads to the trailing edge only in its blade-tip-side region.
Furthermore, it is known from U.S. Pat. No. 6,551,063 to construct the trailing edge of a turbine blade in modules by a plate-like element which covers the trailing edge ribs being soldered on or welded on, in the case of a turbine blade with a so-called “cut-back” trailing edge.
It is disadvantageous to the concepts which are also known as “in-situ blade reheat” that, as a result of the mixing of cooling air and fuel in the components, the reaction partners can ignite as a result of self-ignition or flashback. As a result of this, stable combustion processes are possibly formed inside the turbine blade so that the cooling effect of the fuel-air mixture is lost, or the component can be damaged as a result of the combustion which occurs internally.